Soil conditioning affects interactions between native and invasive exotic perennials of semi-natural grasslands

1. Semi–natural perennial grasslands are of increasing importance as components of multifunctional agroecosystems, combining biomass production with provision of other ecosystem services. Soil legacies from previous land use or exotic species can hinder their establishment, but might be overcome through a multi–stage successional strategy, whereby certain species are used to facilitate native grassland species establishment. We tested this strategy via a feedback experiment examining soil conditioning effects on interference interactions between native and exotic species.
2. Soils in a former maize–soybean production field in Minnesota, USA, were conditioned for three years with native or invasive exotic perennials or a maize–soybean crop rotation. Nitrogen (N) fertilisation was an additional treatment in field plots. In a greenhouse, native and invasive exotic perennial grassland seedlings were grown on these soils, in monoculture and in native–exotic species pairs, with and without ...